Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C271/00—Derivatives of carbamic acids, i.e. compounds containing any of the groups, the nitrogen atom not being part of nitro or nitroso groups
  • C07C271/06—Esters of carbamic acids
  • C07C271/08—Esters of carbamic acids having oxygen atoms of carbamate groups bound to acyclic carbon atoms
  • C07C271/10—Esters of carbamic acids having oxygen atoms of carbamate groups bound to acyclic carbon atoms with the nitrogen atoms of the carbamate groups bound to hydrogen atoms or to acyclic carbon atoms
  • C07C271/22—Esters of carbamic acids having oxygen atoms of carbamate groups bound to acyclic carbon atoms with the nitrogen atoms of the carbamate groups bound to hydrogen atoms or to acyclic carbon atoms to carbon atoms of hydrocarbon radicals substituted by carboxyl groups
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C269/00—Preparation of derivatives of carbamic acid, i.e. compounds containing any of the groups, the nitrogen atom not being part of nitro or nitroso groups
  • C07C269/06—Preparation of derivatives of carbamic acid, i.e. compounds containing any of the groups, the nitrogen atom not being part of nitro or nitroso groups by reactions not involving the formation of carbamate groups
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D309/00—Heterocyclic compounds containing six-membered rings having one oxygen atom as the only ring hetero atom, not condensed with other rings
  • C07D309/02—Heterocyclic compounds containing six-membered rings having one oxygen atom as the only ring hetero atom, not condensed with other rings having no double bonds between ring members or between ring members and non-ring members
  • C07D309/04—Heterocyclic compounds containing six-membered rings having one oxygen atom as the only ring hetero atom, not condensed with other rings having no double bonds between ring members or between ring members and non-ring members with only hydrogen atoms, hydrocarbon or substituted hydrocarbon radicals, directly attached to ring carbon atoms
  • C07D309/06—Radicals substituted by oxygen atoms
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D335/00—Heterocyclic compounds containing six-membered rings having one sulfur atom as the only ring hetero atom
  • C07D335/02—Heterocyclic compounds containing six-membered rings having one sulfur atom as the only ring hetero atom not condensed with other rings
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C2601/00—Systems containing only non-condensed rings
  • C07C2601/12—Systems containing only non-condensed rings with a six-membered ring
  • C07C2601/14—The ring being saturated

Definitions

• Methods for synthesis of 1-(acyloxy)-alkyl carbamates are provided. More particularly, the synthesis of prodrugs (i.e ., 1-(acyloxy)-alkyl carbamates of GABA analogs) from 1-haloalkyl carbamates of GABA analogs are described. Also described are new 1-haloalkyl carbamates of GABA analogs.
• prodrugs One solution to drug delivery and/or bioavailability issues in pharmaceutical development is converting known drugs to prodrugs.
• a polar functional group e.g ., a carboxylic acid, an amino group, a hydroxyl group, etc.
• promoiety which is labile under physiological conditions.
• prodrugs are usually transported through hydrophobic biological barriers such as membranes and typically possess superior physicochemical properties than the parent drug.
• Pharmacologically effective prodrugs are non-toxic and are preferably selectively cleaved at the locus of drug action. Ideally, cleavage of the promoiety occurs rapidly and quantitatively with the formation of non-toxic by-products ( i.e ., the hydrolyzed promoiety).
• acyloxyalkoxycarbonyl functionality is an example of a promoiety that may be used to modulate the physiochemical properties of pharmaceuticals (Alexander, United States Patent No. 4,916,230 ; Alexander, United States Patent No. 5,733,907 ; Alexander et al., U.S. Patent No. 4,426,391 ).
• 1-(acyloxy)-alkyl derivatives of a pharmaceutical possess superior bioavailability may be less irritating to topical and gastric mucosal membranes and are usually more permeable through such membranes when compared to the parent drug.
• a method for synthesizing 1-(acyloxy)-alkyl derivatives from acyloxy derivatives which typically proceeds in high yield, does not necessarily require the use of heavy metals and is readily amenable to scale-up is provided herein.
• a method of synthesizing a compound of Formula ( I ) comprises contacting a compound of Formula ( II ), a compound of Formula ( III ) and at least one equivalent of a metal salt wherein:
• a method of synthesizing a compound of Formula ( I ) comprises contacting a compound of Formula ( II ), a compound of Formula ( III ) and at least one equivalent of an organic base, where X, n, R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 and R 10 are as defined, supra.
• Compounds refers to compounds encompassed by structural formulae ( I ) - ( VIII ) disclosed herein and includes any specific compounds within these formulae whose structure is disclosed herein. Compounds may be identified either by their chemical structure and/or chemical name. When the chemical structure and chemical name conflict, the chemical structure is determinative of the identity of the compound.
• the compounds described herein may contain one or more chiral centers and/or double bonds and therefore, may exist as stereoisomers, such as double-bond isomers ( i.e ., geometric isomers), enantiomers or diastereomers.
• the chemical structures depicted herein encompass all possible enantiomers and stereoisomers of the illustrated compounds including the stereoisomerically pure form (e.g ., geometrically pure, enantiomerically pure or diastereomerically pure) and enantiomeric and stereoisomeric mixtures.
• Enantiomeric and stereoisomeric mixtures can be resolved into their component enantiomers or stereoisomers using separation techniques or chiral synthesis techniques well known to the skilled artisan.
• the compounds may also exist in several tautomeric forms including the enol form, the keto form and mixtures thereof. Accordingly, the chemical structures depicted herein encompass all possible tautomeric forms of the illustrated compounds.
• the compounds described also include isotopically labeled compounds where one or more atoms have an atomic mass different from the atomic mass conventionally found in nature.
• isotopes that may be incorporated into the compounds of the invention include, but are not limited to, 2 H, 3 H, 13 C, 14 C, 15 N, 18 O, 17 O, etc .
• Compounds may exist in unsolvated forms as well as solvated forms, including hydrated forms and as N-oxides. In general, compounds may be hydrated, solvated or N-oxides. Certain compounds may exist in multiple crystalline or amorphous forms. In general, all physical forms are equivalent for the uses contemplated herein and are intended to be within the scope of the present invention. Further, it should be understood, when partial structures of the compounds are illustrated, that brackets indicate the point of attachment of the partial structure to the rest of the molecule.
• 1-Acyloxy-Alkyl Carbamate refers to an N-1-acyloxy-alkoxycarbonyl derivative of a primary or secondary amine as encompassed by structural formulae ( I ), ( V ) and ( VI ) disclosed herein.
• Alkyl by itself or as part of another substituent refers to a saturated or unsaturated, branched, straight-chain or cyclic monovalent hydrocarbon radical derived by the removal of one hydrogen atom from a single carbon atom of a parent alkane, alkene or alkyne.
• Typical alkyl groups include, but are not limited to, methyl; ethyls such as ethanyl, ethenyl, ethynyl; propyls such as propan-1-yl, propan-2-yl, cyclopropan-1-yl, prop-1-en-1-yl, prop-1-en-2-yl, prop-2-en-1-yl (allyl), cycloprop-1-en-1-yl; cycloprop-2-en-1-yl, prop-1-yn-1-yl, prop-2-yn-1-yl, etc .; butyls such as butan-1-yl, butan-2-yl, 2-methyl-propan-1-yl, 2-methyl-propan-2-yl, cyclobutan-1-yl, but-1-en-1-yl, but-1-en-2-yl, 2-methyl-prop-1-en-1-yl, but-2-en-2-yl, buta-1
• alkyl is specifically intended to include groups having any degree or level of saturation, i.e ., groups having exclusively single carbon-carbon bonds, groups having one or more double carbon-carbon bonds, groups having one or more triple carbon-carbon bonds and groups having mixtures of single, double and triple carbon-carbon bonds. Where a specific level of saturation is intended, the expressions “alkanyl,” “alkenyl,” and “alkynyl” are used.
• an alkyl group comprises from 1 to 20 carbon atoms, more preferably, from 1 to 10 carbon atoms, most preferably, from 1 to 6 carbon atoms.
• Alkanyl by itself or as part of another substituent refers to a saturated branched, straight-chain or cyclic alkyl radical derived by the removal of one hydrogen atom from a single carbon atom of a parent alkane.
• Typical alkanyl groups include, but are not limited to, methanyl; ethanyl; propanyls such as propan-1-yl, propan-2-yl (isopropyl), cyclopropan-1-yl, etc .; butanyls such as butan-1-yl, butan-2-yl ( sec -butyl), 2-methyl-propan-1-yl (isobutyl), 2-methyl-propan-2-yl ( t -butyl), cyclobutan-1-yl, etc .; and the like.
• Alkenyl by itself or as part of another substituent refers to an unsaturated branched, straight-chain or cyclic alkyl radical having at least one carbon-carbon double bond derived by the removal of one hydrogen atom from a single carbon atom of a parent alkene.
• the group may be in either the cis or trans conformation about the double bond(s).
• Typical alkenyl groups include, but are not limited to, ethenyl; propenyls such as prop-1-en-1-yl, prop-1-en-2-yl, prop-2-en-1-yl (allyl), prop-2-en-2-yl, cycloprop-1-en-1-yl; cycloprop-2-en-1-yl; butenyls such as but-1-en-1-yl, but-1-en-2-yl, 2-methyl-prop-1-en-1-yl, but-2-en-1-yl, but-2-en-1-yl, but-2-en-2-yl, buta-1,3-dien-1-yl, buta-1,3-dien-2-yl, cyclobut-1-en-1-yl, cyclobut-1-en-3-yl, cyclobuta-1,3-dien-1-yl, etc.; and the like.
• Alkynyl by itself or as part of another substituent refers to an unsaturated branched, straight-chain or cyclic alkyl radical having at least one carbon-carbon triple bond derived by the removal of one hydrogen atom from a single carbon atom of a parent alkyne.
• Typical alkynyl groups include, but are not limited to, ethynyl; propynyls such as prop-1-yn-1-yl, prop-2-yn-1-yl, etc .; butynyls such as but-1-yn-1-yl, but-1-yn-3-yl, but-3-yn-1-yl, etc .; and the like.
• Acyl by itself or as part of another substituent refers to a radical -C(O)R 30 , where R 30 is hydrogen, alkyl, cycloalkyl, cycloheteroalkyl, aryl, arylalkyl, heteroalkyl, heteroaryl, heteroarylalkyl as defined herein.
• Representative examples include, but are not limited to formyl, acetyl, cyclohexylcarbonyl, cyclohexylmethylcarbonyl, benzoyl, benzylcarbonyl and the like.
• Alkoxy by itself or as part of another substituent refers to a radical -OR 31 where R 31 represents an alkyl or cycloalkyl group as defined herein. Representative examples include, but are not limited to, methoxy, ethoxy, propoxy, butoxy, cyclohexyloxy and the like.
• Alkoxycarbonyl by itself or as part of another substituent refers to a radical -OR 32 where R 32 represents an alkyl or cycloalkyl group as defined herein. Representative examples include, but are not limited to, methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, butoxycarbonyl, cyclohexyloxycarbonyl and the like.
• Aryl by itself or as part of another substituent refers to a monovalent aromatic hydrocarbon radical derived by the removal of one hydrogen atom from a single carbon atom of a parent aromatic ring system.
• Typical aryl groups include, but are not limited to, groups derived from aceanthrylene, acenaphthylene, acephenanthrylene, anthracene, azulene, benzene, chrysene, coronene, fluoranthene, fluorene, hexacene, hexaphene, hexalene, as -indacene, s-indacene, indane, indene, naphthalene, octacene, octaphene, octalene, ovalene, penta-2,4-diene, pentacene, pentalene, pentaphene, perylene, phenalene, phenanthrene, pic
• Arylalkyl by itself or as part of another substituent refers to an acyclic alkyl radical in which one of the hydrogen atoms bonded to a carbon atom, typically a terminal or sp 3 carbon atom, is replaced with an aryl group.
• Typical arylalkyl groups include, but are not limited to, benzyl, 2-phenylethan-1-yl, 2-phenylethen-1-yl, naphthylmethyl, 2-naphthylethan-1-yl, 2-naphthylethen-1-yl, naphthobenzyl, 2-naphthophenylethan-1-yl and the like.
• an arylalkyl group is (C 6 -C 30 ) arylalkyl, e.g ., the alkanyl, alkenyl or alkynyl moiety of the arylalkyl group is (C 1 -C 10 ) and the aryl moiety is (C 6 -C 20 ), more preferably, an arylalkyl group is (C 6 -C 20 ) arylalkyl, e.g ., the alkanyl, alkenyl or alkynyl moiety of the arylalkyl group is (C 1 -C 8 ) and the aryl moiety is (C 6 -C 12 ).
• Aryldialkylsilyl by itself or as part of another substituent refers to the radical - SiR 33 R 34 R 35 where one of R 33 , R 34 or R 35 is aryl as defined herein and the other two of R 33 , R 34 or R 35 are alkyl as defined herein.
• Bridged cycloalkyl by itself or as part of another substituent refers to a radical selected from the group consisting of wherein:
• Carbamoyl by itself or as part of another substituent refers to the radical -C(O)NR 40 R 41 where R 40 and R 41 are independently hydrogen, alkyl, cycloalkyl or aryl as defined herein.
• Cycloalkyl by itself or as part of another substituent refers to a saturated or unsaturated cyclic alkyl radical. Where a specific level of saturation is intended, the nomenclature “cycloalkanyl” or “cycloalkenyl” is used.
• Typical cycloalkyl groups include, but are not limited to, groups derived from cyclopropane, cyclobutane, cyclopentane, cyclohexane and the like.
• the cycloalkyl group is (C 3 -C 10 ) cycloalkyl, more preferably (C 3 -C 7 ) cycloalkyl.
• Cycloheteroalkyl by itself or as part of another substituent refers to a saturated or unsaturated cyclic alkyl radical in which one or more carbon atoms (and any associated hydrogen atoms) are independently replaced with the same or different heteroatom.
• Typical heteroatoms to replace the carbon atom(s) include, but are not limited to, N, P, O, S, Si, etc. Where a specific level of saturation is intended, the nomenclature “cycloheteroalkanyl” or “cycloheteroalkenyl” is used.
• Typical cycloheteroalkyl groups include, but are not limited to, groups derived from epoxides, azirines, thiiranes, imidazolidine, morpholine, piperazine, piperidine, pyrazolidine, pyrrolidine, quinuclidine, and the like.
• GABA analog refers to a compound, unless specified otherwise, as having the following structure: wherein:
• 1-Haloalkyl Carbamate refers to an N-1-haloalkoxycarbonyl derivative of a primary or secondary amine as encompassed by structural formulae ( II ), ( VII ) and ( VIII ) disclosed herein.
• Heteroalkyl, Heteroalkanyl, Heteroalkenyl and Heteroalkynyl by themselves or as part of another substituent refer to alkyl, alkanyl, alkenyl and alkynyl groups, respectively, in which one or more of the carbon atoms (and any associated hydrogen atoms) are independently replaced with the same or different heteroatomic groups.
• Heteroaryl by itself or as part of another substituent refers to a monovalent heteroaromatic radical derived by the removal of one hydrogen atom from a single atom of a parent heteroaromatic ring system.
• Typical heteroaryl groups include, but are not limited to, groups derived from acridine, arsindole, carbazole, ⁇ -carboline, chromane, chromene, cinnoline, furan, imidazole, indazole, indole, indoline, indolizine, isobenzofuran, isochromene, isoindole, isoindoline, isoquinoline, isothiazole, isoxazole, naphthyridine, oxadiazole, oxazole, perimidine, phenanthridine, phenanthroline, phenazine, phthalazine, pteridine, purine, pyran, pyrazine,
• the heteroaryl group is from 5-20 membered heteroaryl, more preferably from 5-10 membered heteroaryl.
• Preferred heteroaryl groups are those derived from thiophene, pyrrole, benzothiophene, benzofuran, indole, pyridine, quinoline, imidazole, oxazole and pyrazine
• Heteroarylalkyl by itself or as part of another substituent refers to an acyclic alkyl radical in which one of the hydrogen atoms bonded to a carbon atom, typically a terminal or sp 3 carbon atom, is replaced with a heteroaryl group. Where specific alkyl moieties are intended, the nomenclature heteroarylalkanyl, heteroarylalkenyl and/or heterorylalkynyl is used.
• the heteroarylalkyl group is a 6-30 membered heteroarylalkyl, e.g ., the alkanyl, alkenyl or alkynyl moiety of the heteroarylalkyl is 1-10 membered and the heteroaryl moiety is a 5-20-membered heteroaryl, more preferably, 6-20 membered heteroarylalkyl, e.g ., the alkanyl, alkenyl or alkynyl moiety of the heteroarylalkyl is 1-8 membered and the heteroaryl moiety is a 5-12-membered heteroaryl.
• Parent Aromatic Ring System refers to an unsaturated cyclic or polycyclic ring system having a conjugated ⁇ electron system. Specifically included within the definition of "parent aromatic ring system” are fused ring systems in which one or more of the rings are aromatic and one or more of the rings are saturated or unsaturated, such as, for example, fluorene, indane, indene, phenalene, etc .
• Typical parent aromatic ring systems include, but are not limited to, aceanthrylene, acenaphthylene, acephenanthrylene, anthracene, azulene, benzene, chrysene, coronene, fluoranthene, fluorene, hexacene, hexaphene, hexalene, as-indacene, s-indacene, indane, indene, naphthalene, octacene, octaphene, octalene, ovalene, penta-2,4-diene, pentacene, pentalene, pentaphene, perylene, phenalene, phenanthrene, picene, pleiadene, pyrene, pyranthrene, rubicene, triphenylene, trinaphthalene and the like.
• Parent Heteroaromatic Ring System refers to a parent aromatic ring system in which one or more carbon atoms (and any associated hydrogen atoms) are independently replaced with the same or different heteroatom. Typical heteroatoms to replace the carbon atoms include, but are not limited to, N, P, O, S, Si, etc . Specifically included within the definition of "parent heteroaromatic ring systems” are fused ring systems in which one or more of the rings are aromatic and one or more of the rings are saturated or unsaturated, such as, for example, arsindole, benzodioxan, benzofuran, chromane, chromene, indole, indoline, xanthene, etc .
• Typical parent heteroaromatic ring systems include, but are not limited to, arsindole, carbazole, ⁇ -carboline, chromane, chromene, cinnoline, furan, imidazole, indazole, indole, indoline, indolizine, isobenzofuran, isochromene, isoindole, isoindoline, isoquinoline, isothiazole, isoxazole, naphthyridine, oxadiazole, oxazole, perimidine, phenanthridine, phenanthroline, phenazine, phthalazine, pteridine, purine, pyran, pyrazine, pyrazole, pyridazine, pyridine, pyrimidine, pyrrole, pyrrolizine, quinazoline, quinoline, quinolizine, quinoxaline, tetrazole, thi
• Pharmaceutically acceptable salt refers to a salt of a compound, which possesses the desired pharmacological activity of the parent compound.
• Such salts include: (1) acid addition salts, formed with inorganic acids such as hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid, and the like; or formed with organic acids such as acetic acid; propionic acid, hexanoic acid, cyclopentanepropionic acid, glycolic acid, pyruvic acid, lactic acid, malonic acid, succinic acid, malic acid, maleic acid, fumaric acid, tartaric acid, citric acid, benzoic acid, 3-(4-hydroxybenzoyl) benzoic acid, cinnamic acid, mandelic acid, methanesulfonic acid, ethanesulfonic acid, 1,2-ethane-disulfonic acid, 2-hydroxyethanesulfonic acid, benzenesulfonic acid, 4-chlorobenzen
• Prodrug refers to a derivative of a drug molecule that requires a transformation within the body to release the active drug. Prodrugs are frequently, although not necessarily, pharmacologically inactive until converted to the parent drug.
• a hydroxyl containing drug may be converted to, for example, to a sulfonate, ester or carbonate prodrug, which may be hydrolyzed in vivo to provide the hydroxyl compound.
• An amino containing drug may be converted, for example, to a carbamate, amide, enamine, imine, N-phosphonyl, N-phosphoryl or N-sulfenyl prodrug, which may be hydrolyzed in vivo to provide the amino compound.
• a carboxylic acid drug may be converted to an ester (including silyl esters and thioesters), amide or hydrazide prodrug, which be hydrolyzed in vivo to provide the carboxylic acid compound.
• ester including silyl esters and thioesters
• amide or hydrazide prodrug which be hydrolyzed in vivo to provide the carboxylic acid compound.
• Prodrugs for drugs which have functional groups different than those listed above are well known to the skilled artisan.
• Promoiety refers to a form of protecting group that when used to mask a functional group within a drug molecule converts the drug into a prodrug. Typically, the promoiety will be attached to the drug via bond(s) that are cleaved by enzymatic or non-enzymatic means in vivo.
• Protecting group refers to a grouping of atoms that when attached to a reactive functional group in a molecule masks, reduces or prevents reactivity of the functional group. Examples of protecting groups can be found in Green et al., “Protective Groups in Organic Chemistry", (Wiley, 2nd ed. 1991 ) and Harrison et al., “Compendium of Synthetic Organic Methods", Vols. 1-8 (John Wiley and Sons, 1971-1996 ).
• Representative amino protecting groups include, but are not limited to, formyl, acetyl, trifluoroacetyl, benzyl, benzyloxycarbonyl ("CBZ”), tert -butoxycarbonyl (“Boc”), trimethylsilyl (“TMS”), 2-trimethylsilyl-ethanesulfonyl (“SES”), trityl and substituted trityl groups, allyloxycarbonyl, 9-fluorenylinethyloxycarbonyl (“FMOC”), nitro-veratryloxycarbonyl (“NVOC”) and the like.
• hydroxy protecting groups include, but are not limited to, those where the hydroxy group is either acylated or alkylated such as benzyl, and trityl ethers as well as alkyl ethers, tetrahydropyranyl ethers, trialkylsilyl ethers and allyl ethers.
• Substituted refers to a group in which one or more hydrogen atoms are independently replaced with the same or different substituent(s).
• Trialkylsilyl by itself or as part of another substituent refers to a radical - SiR 50 R 51 R 52 where R 50 , R 51 and R 52 are alkyl as defined herein.
• 1-(acyloxy)-alkyl carbamates of GABA analogs are synthesized by reaction of a 1-haloalkyl carbamate of a GABA analog with a carboxylic acid in the presence of either a metal salt or an organic base.
• the carboxylic acid also serves a solvent for the reaction.
• a compound of Formula (I) is synthesized by a method comprising contacting a compound of Formula ( II ), a compound of Formula ( III ) and at least one equivalent of a metal salt wherein:
• a compound of Formula ( I ) is synthesized by a method comprising contacting a compound of Formula ( II ), a compound of Formula ( III ) and at least one equivalent of an organic base, wherein X, n, R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 and R 10 are as defined, supra.
• R 2 and R 3 are independently hydrogen, alkyl, substituted alkyl, alkoxycarbonyl, substituted alkoxycarbonyl, aryl, substituted aryl, arylalkyl, substituted arylalkyl, carbamoyl, substituted carbamoyl, cycloalkyl, substituted cycloalkyl, heteroaryl or substituted heteroaryl.
• R 2 and R 3 are independently hydrogen, alkyl, alkoxycarbonyl, aryl, arylalkyl, carbamoyl, cycloalkyl, or heteroaryl.
• R 2 and R 3 are independently hydrogen, alkanyl or substituted alkanyl.
• R 2 and R 3 are independently hydrogen or alkanyl.
• R 1 is alkyl, substituted alkyl, aryl, substituted aryl, arylalkyl, substituted arylalkyl, cycloalkyl, substituted cycloalkyl, heteroalkyl, substituted heteroalkyl, heteroaryl or substituted heteroaryl.
• R 1 is alkyl or substituted alkyl.
• R 1 is alkanyl or substituted alkanyl.
• R 1 is alkyl, substituted alkyl, aryl, substituted aryl, arylalkyl, substituted arylalkyl, cycloalkyl, substituted cycloalkyl, heteroalkyl, substituted heteroalkyl, heteroaryl or substituted heteroaryl
• R 2 and R 3 are independently hydrogen, alkyl, substituted alkyl, alkoxycarbonyl, substituted alkoxycarbonyl, aryl, substituted aryl, arylalkyl, substituted arylalkyl, carbamoyl, cycloalkyl, substituted cycloalkyl, heteroaryl, substituted heteroaryl, heteroarylalkyl or substituted heteroarylalkyl.
• R 1 is alkyl, substituted alkyl, aryl, arylalkyl or heteroaryl and R 2 and R 3 are independently hydrogen, alkyl, substituted alkyl, alkoxycarbonyl, substituted alkoxycarbonyl, aryl, substituted aryl, arylalkyl, substituted arylalkyl, carbamoyl, cycloalkyl, substituted cycloalkyl, heteroaryl, substituted heteroaryl, heteroarylalkyl or substituted heteroarylalkyl.
• R 1 is alkanyl or substituted alkanyl and R 2 and R 3 are independently hydrogen, alkyl, substituted alkyl, alkoxycarbonyl, substituted alkoxycarbonyl, aryl, substituted aryl, arylalkyl, substituted arylalkyl, carbamoyl, cycloalkyl, substituted cycloalkyl, heteroaryl, substituted heteroaryl, heteroarylalkyl or substituted heteroarylalkyl.
• R 1 is alkyl, substituted alkyl, aryl, substituted aryl, arylalkyl, substituted arylalkyl, cycloalkyl or substituted cycloalkyl and R 2 and R 3 are independently hydrogen, alkyl, alkoxycarbonyl, aryl, arylalkyl, carbamoyl, cycloalkyl or heteroaryl.
• R 1 is alkyl, substituted alkyl, aryl, substituted aryl, arylalkyl, substituted arylalkyl, cycloalkyl or substituted cycloalkyl and R 2 and R 3 are independently hydrogen, alkanyl or substituted alkanyl.
• R 1 is alkyl, substituted alkyl, aryl,substituted aryl, arylalkyl, substituted arylalkyl, cycloalkyl or substituted cycloalkyl and R 2 and R 3 are independently alkanyl.
• R 1 is alkyl, substituted alkyl, aryl, substituted aryl, arylalkyl, substituted arylalkyl, cycloalkyl, substituted cycloalkyl, heteroaryl or substituted heteroaryl and R 2 and R 3 together with the atom to which they are attached form a cycloalkyl, substituted cycloalkyl, cycloheteroalkyl or substituted cycloheteroalkyl ring.
• R 1 is alkyl, substituted alkyl, aryl, arylalkyl, cycloalkyl or heteroaryl and R 2 and R 3 are independently hydrogen, alkyl, alkoxycarbonyl, aryl, arylalkyl, carbamoyl, cycloalkyl or heteroaryl.
• R 1 is alkyl, substituted alkyl, aryl, arylalkyl, cycloalkyl or heteroaryl and R 2 and R 3 are independently hydrogen, alkanyl or substituted alkanyl.
• R 1 is alkyl, substituted alkyl, aryl, arylalkyl, cycloalkyl or heteroaryl and R 2 and R 3 are independently alkanyl.
• R 1 is alkyl, substituted alkyl, aryl, arylalkyl, cycloalkyl or heteroaryl and R 2 and R 3 together with the atom to which they are attached form a cycloalkyl, substituted cycloalkyl, cycloheteroalkyl or substituted cycloheteroalkyl ring.
• R 1 is alkanyl or substituted alkanyl and R 2 and R 3 are independently hydrogen, alkyl, alkoxycarbonyl, aryl, arylalkyl, carbamoyl, cycloalkyl or heteroaryl.
• R 1 is alkanyl or substituted alkanyl and R 2 and R 3 are independently hydrogen, alkanyl or substituted alkanyl.
• R 1 is alkanyl or substituted alkanyl and R 2 and R 3 are independently alkanyl.
• R 1 is alkanyl or substituted alkanyl
• R 2 and R 3 together with the atom to which they are attached form a cycloalkyl, substituted cycloalkyl, cycloheteroalkyl or substituted cycloheteroalkyl ring.
• R 1 is methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec -butyl, tert -butyl, pentyl, isopentyl, sec -pentyl, neopentyl, 1,1-dimethoxyethyl, 1,1-diethoxyethyl, cyclobutyl, cyclopentyl, cyclohexyl, phenyl, 4-methoxyphenyl, benzyl, phenethyl, styryl or 3-pyridyl.
• R 2 and R 3 are independently hydrogen, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec -butyl, tert -butyl, cyclobutyl, cyclopentyl, cyclohexyl, methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, isopropoxycarbonyl, butoxycarbonyl, isobutoxycarbonyl, sec -butoxycarbonyl, tert -butoxycarbonyl, cyclohexyloxycarbonyl, phenyl, benzyl, phenethyl or 3-pyridyl.
• R 1 is methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec -butyl, ten-butyl, pentyl, isopentyl, sec -pentyl, neopentyl, 1,1-dimethoxyethyl, 1,1-diethoxyethyl, cyclobutyl, cyclopentyl, cyclohexyl, phenyl, 4-methoxyphenyl, benzyl, phenethyl, styryl or 3-pyridyl and R 2 and R 3 are independently hydrogen, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec -butyl, tert -butyl, cyclobutyl, cyclopentyl, cyclohexyl, methoxycarbonyl, ethoxycarbonyl, propoxycarbon
• R 2 is methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec -butyl, tert -butyl, pentyl, isopentyl, sec -pentyl, neopentyl, 1,1-dimethoxyethyl, 1,1-diethoxyethyl, cyclobutyl, cyclopentyl, cyclohexyl, phenyl, 4-methoxyphenyl, benzyl, phenethyl, styryl or 3-pyridyl and R 2 and R 3 together with the atom to which they are attached form a cyclobutyl, cyclopentyl or cyclohexyl ring.
• R 2 is methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec -butyl, tert -butyl, cyclohexyl or phenyl and R 3 is hydrogen.
• R 2 is methyl, methoxycarbonyl, ethoxycarbonyl, isopropoxycarbonyl or cyclohexyloxycarbonyl and R 3 is methyl.
• R 2 is methyl, ethyl, n -propyl, isopropyl, n -butyl, isobutyl, sec -butyl, tert -butyl, 1,1-dimethoxyethyl or 1,1-diethoxyethyl.
• R 2 is methyl, ethyl, n -propyl, isopropyl, n -butyl, isobutyl, sec -butyl or tert -butyl, and R 3 is hydrogen.
• R 1 is methyl, ethyl, n -propyl, isopropyl, n -butyl, isobutyl, sec -butyl, tert -butyl, 1,1-dimethoxyethyl or 1,1-diethoxyethyl
• R 2 is methyl, ethyl, n -propyl, isopropyl, n -butyl, isobutyl, sec -butyl or tert -butyl
• R 3 is hydrogen.
• R 10 is hydrogen, alkyl, substituted alkyl, aryl, substituted aryl, arylalkyl, substituted arylalkyl, aryldialkylsilyl, cycloalkyl, substituted cycloalkyl, cycloheteroalkyl, substituted cycloheteroalkyl, heteroalkyl, substituted heteroalkyl, heteroaryl, substituted heteroaryl, heteroarylalkyl, substituted heteroarylalkyl or trialkylsilyl.
• R 10 is hydrogen.
• R 10 is alkanyl, substituted alkanyl, alkenyl, substituted alkenyl, aryl, substituted aryl, arylalkyl, substituted arylalkyl, aryldialkylsilyl or trialkylsilyl.
• n is 0. In another embodiment, n is 1.
• R 5 is selected from the group consisting of hydrogen, alkanyl, substituted alkanyl, aryl, substituted aryl, arylalkanyl, substituted arylalkanyl, cycloalkanyl, heteroarylalkyl and substituted heteroarylalkanyl.
• R 5 is selected from the group consisting of hydrogen, alkanyl and cycloalkanyl.
• R 5 is selected from the group consisting of hydrogen, methyl, isopropyl, isobutyl, sec -butyl, tert -butyl, cyclopentyl and cyclohexyl.
• R 5 is selected from the group consisting of substituted alkanyl.
• R 5 is selected from the group consisting of -CH 2 OH, -CH(OH)CH 3 , -CH 2 CO 2 H, -CH 2 CH 2 CO 2 H, -CH 2 CONH 2 , -CH 2 CH 2 CONH 2 , - CH 2 CH 2 SCH 3 , CH 2 SH, -CH 2 (CH 2 ) 3 NH 2 and -CH 2 CH 2 CH 2 NHC(NH)NH 2 .
• R 5 is selected from the group consisting of aryl, arylalkanyl, substituted arylalkanyl and heteroarylalkanyl.
• R 5 is selected from the group consisting of phenyl, benzyl, 4-hydroxybenzyl, 4-bromobenzyl, 4-imidazolylmethyl and 3-indolylmethyl.
• R 4 and R 5 together with the atoms to which they are attached form a cycloheteroalkyl or substituted cycloheteroalkyl ring. In still another embodiment, R 4 and R 5 together with the atoms to which they are attached form an azetidine, pyrrolidine or piperidine ring.
• R 6 and R 9 are independently selected from the group consisting of hydrogen, alkyl, substituted alkyl, aryl, substituted aryl, cycloalkyl and substituted cycloalkyl. In another embodiment, R 6 and R 9 are independently selected from the group consisting of hydrogen and alkanyl. In still another embodiment, R 6 and R 9 are both hydrogen.
• R 7 and R 8 are independently selected from the group consisting of hydrogen; alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl, cycloheteroalkyl and substituted cycloheteroalkyl. In another embodiment, R 7 and R 8 are independently selected from the group consisting of hydrogen, alkanyl and substituted alkanyl. In still another embodiment, R 7 is hydrogen and R 8 is selected from the group consisting of C 1-6 alkanyl.
• R 7 and R 8 together with the carbon atom to which they are attached are cycloalkanyl or substituted cycloalkanyl. In still another embodiment, R 7 and R 8 together with the carbon atom to which they are attached are selected from the group consisting of cyclobutyl, substituted cyclobutyl, cyclopentyl, substituted cyclopentyl, cyclohexyl and substituted cyclohexyl.
• R 7 and R 8 together with the carbon atom to which they are attached are cycloheteroalkyl or substituted cycloheteroalkyl. In still another embodiment, R 7 and R 8 together with the carbon atom to which they are attached are bridged cycloalkyl.
• X is chloro, bromo or iodo. In another embodiment, X is chloro, and R 2 and R 3 are independently hydrogen or alkanyl. In still another embodiment, X is chloro, and R 2 and R 3 together with the atom to which they are attached form a cycloalkanyl ring.
• X is chloro, bromo or iodo
• R 2 and R 3 are independently hydrogen, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec -butyl, tert -butyl, cyclobutyl, cyclopentyl, cyclohexyl, methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, isopropoxycarbonyl, butoxycarbonyl, isobutoxycarbonyl, sec -butoxycarbonyl, tert -butoxycarbonyl, cyclohexyloxycarbonyl, phenyl, benzyl, phenethyl or 3-pyridyl.
• X is chloro, bromo or iodo
• R 2 and R 3 together with the atom to which they are attached form a cyclobutyl, cyclopentyl or cyclohexyl ring.
• X is chloro, bromo or iodo
• R 2 is methyl, ethyl, n -propyl, isopropyl, n -butyl, isobutyl, sec -butyl, tert -butyl, cyclohexyl or phenyl and R 3 is hydrogen.
• a compound of Formulae ( I ) or ( II ) is derived is derived from a GABA analog of Formula ( IV ): wherein the GABA analog of Formula ( IV ) is selected from the group consisting of:
• the compound of Formula ( I ) is a compound of Formulae ( V ) or ( VI ):
• n is 0. In another embodiment n is 1.
• R 5 is selected from the group consisting of hydrogen, alkanyl, substituted alkanyl, aryl, substituted aryl, arylalkanyl, substituted arylalkanyl, cycloalkanyl, heteroarylalkyl and substituted heteroarylalkanyl.
• R 5 is selected from the group consisting of hydrogen, methyl, isopropyl, isobutyl, sec -butyl, tert- butyl, cyclopentyl, cyclohexyl, -CH 2 OH, -CH(OH)CH 3 , -CH 2 COH, -CH 2 CH 2 CO 2 H, -CH 2 CONH 2 , -CH 2 CH 2 CONH 2 , - CH 2 CH 2 SCH 3 , CH 2 SH, -CH 2 (CH 2 ) 3 MH 2 and -CH 2 CH 2 CH 2 NHC(NH)NH 2 , phenyl, benzyl, 4-hydroxybenzyl, 4-bromobenzyl, 4-imidazolylmethyl and 3-indolylmethyl.
• R 4 and R 5 together with the atoms to which they are attached form a cycloheteroalkyl or substituted cycloheteroalkyl ring. In still another embodiment, R 4 and R 5 together with the atoms to which they are attached form an azetidine, pyrrolidine or piperidine ring.
• R 1 is methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec -butyl, tert -butyl, pentyl, isopentyl, sec -pentyl, neopentyl, 1,1-dimethoxyethyl, 1,1-diethoxyethyl, cyclobutyl, cyclopentyl, cyclohexyl, phenyl, 4-methoxyphenyl, benzyl, phenethyl, styryl or 3-pyridyl, R 2 is hydrogen and R 3 is hydrogen.
• R 1 is methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec -butyl, tert -butyl, pentyl, isopentyl, sec -pentyl, neopentyl, 1,1,-dimethoxyethyl, 1,1-diethoxyethyl, cyclobutyl, cyclopentyl, cyclohexyl, phenyl, 4-methoxyphenyl, benzyl, phenethyl, styryl or 3-pyridyl, R 2 is methyl and R 3 is hydrogen.
• R 1 is methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec -butyl, tert -butyl, pentyl, isopentyl, sec -pentyl, neopentyl, 1,1-dimethoxyethyl, 1,1-diethoxyethyl, cyclobutyl, cyclopentyl, cyclohexyl, phenyl, 4-methoxyphenyl, benzyl, phenethyl, styryl or 3-pyridyl, R 2 is ethyl and R 3 is hydrogen.
• R 1 is methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec -butyl, tert -butyl, pentyl, isopentyl, sec -pentyl, neopentyl, 1,1-dimethoxyethyl, 1,1-diethoxyethyl, cyclobutyl, cyclopentyl, cyclohexyl, phenyl, 4-methoxyphenyl, benzyl, phenethyl, styryl or 3-pyridyl, R 2 is propyl and R 3 is hydrogen.
• R 1 is methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec -butyl, tert -butyl, pentyl, isopentyl, sec -pentyl, neopentyl, 1,1-dimethoxyethyl, 1,1-diethoxyethyl, cyclobutyl, cyclopentyl, cyclohexyl, phenyl, 4-methoxyphenyl, benzyl, phenethyl, styryl or 3-pyridyl, R 2 is isopropyl and R 3 is hydrogen.
• R 1 is methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec -butyl, tert -butyl, pentyl, isopentyl, sec -pentyl, neopentyl, 1,1-dimethoxyethyl, 1,1-diethoxyethyl, cyclobutyl, cyclopentyl, cyclohexyl, phenyl, 4-methoxyphenyl, benzyl, phenethyl, styryl or 3-pyridyl, R 2 is butyl and R 3 is hydrogen.
• R 1 is methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec -butyl, tert -butyl, pentyl, isopentyl, sec -pentyl, neopentyl, 1,1-dimethoxyethyl, 1,1-diethoxyethyl, cyclobutyl, cyclopentyl, cyclohexyl, phenyl, 4-methoxyphenyl, benzyl, phenethyl, styryl or 3-pyridyl, R 2 is isobutyl and R 3 is hydrogen.
• R 1 is methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec -butyl, tert -butyl, pentyl, isopentyl, sec -pentyl, neopentyl, 1,1-dimethoxyethyl, 1,1-diethoxyethyl, cyclobutyl, cyclopentyl, cyclohexyl, phenyl, 4-methoxyphenyl, benzyl, phenethyl, styryl or 3-pyridyl, R 2 is sec -butyl and R 3 is hydrogen.
• R 1 is methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec -butyl, tert -butyl, pentyl, isopentyl, sec -pentyl, neopentyl, 1,1-dimethoxyethyl, 1,1-diethoxyethyl, cyclobutyl, cyclopentyl, cyclohexyl, phenyl, 4-methoxyphenyl, benzyl, phenethyl, styryl or 3-pyridyl, R 2 is tert -butyl and R 3 is hydrogen.
• R 1 is methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec -butyl, tert -butyl, pentyl, isopentyl, sec -pentyl, neopentyl, 1,1-dimethoxyethyl, 1,1-diethoxyethyl, cyclobutyl, cyclopentyl, cyclohexyl, phenyl, 4-methoxyphenyl, benzyl, phenethyl, styryl or 3-pyridyl, R 2 is cyclohexyl and R 3 is hydrogen.
• R 1 is methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec -butyl, tert -butyl, pentyl, isopentyl, sec -pentyl, neopentyl, 1,1-dimethoxyethyl, 1,1-diethoxyethyl, cyclobutyl, cyclopentyl, cyclohexyl, phenyl, 4-methoxyphenyl, benzyl, phenethyl, styryl or 3-pyridyl, R 2 is phenyl and R 3 is hydrogen.
• R 1 is methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec -butyl, tert -butyl, pentyl, isopentyl, sec -pentyl, neopentyl, 1,1-dimethoxyethyl, 1,1-diethoxyethyl, cyclobutyl, cyclopentyl, cyclohexyl, phenyl, 4-methoxyphenyl, benzyl, phenethyl, styryl or 3-pyridyl, R 2 is methyl and R 3 is methyl.
• R 1 is methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec -butyl, tert -butyl, pentyl, isopentyl, sec -pentyl, neopentyl, 1,1-dimethoxyethyl, 1,1-diethoxyethyl, cyclobutyl, cyclopentyl, cyclohexyl, phenyl, 4-methoxyphenyl, benzyl, phenethyl, styryl or 3-pyridyl, R 2 is methoxycarbonyl and R 3 is methyl.
• R 1 is methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec -butyl, tert -butyl, pentyl, isopentyl, sec -pentyl, neopentyl, 1,1-dimethoxyethyl, 1,1-diethoxyethyl, cyclobutyl, cyclopentyl, cyclohexyl, phenyl, 4-methoxyphenyl, benzyl, phenethyl, styryl or 3-pyridyl, R 2 is ethoxycarbonyl and R 3 is methyl.
• R 1 is methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec -butyl, tert -butyl, pentyl, isopentyl, sec -pentyl, neopentyl, 1,1-dimethoxyethyl, 1,1-diethoxyethyl, cyclobutyl, cyclopentyl, cyclohexyl, phenyl, 4-methoxyphenyl, benzyl, phenethyl, styryl or 3-pyridyl, R 2 is isopropoxycarbonyl and R 3 is methyl.
• R 1 is methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec -butyl, tert -butyl, pentyl, isopentyl, sec -pentyl, neopentyl, 1,1-dimethoxyethyl, 1,1-diethoxyethyl, cyclobutyl, cyclopentyl, cyclohexyl, phenyl, 4-methoxyphenyl, benzyl, phenethyl, styryl or 3-pyridyl, R 2 is cyclohexyloxycarbonyl and R 3 is methyl.
• R 1 is methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec -butyl, tert -butyl, pentyl, isopentyl, sec -pentyl, neopentyl, 1,1-dimethoxyethyl, 1,1-diethoxyethyl, cyclobutyl, cyclopentyl, cyclohexyl, phenyl, 4-methoxyphenyl, benzyl, phenethyl, styryl or 3-pyridyl and R 2 and R 3 together with the atom to which they are attached form a cyclohexyl ring.
• R 2 is methyl, methoxycarbonyl, ethoxycarbonyl, isopropoxycarbonyl or cyclohexyloxycarbonyl and R 3 is methyl.
• R 2 is hydrogen, methyl, ethyl, n -propyl, isopropyl, n -butyl, isobutyl, sec -butyl or tert -butyl and R 3 is hydrogen.
• R 1 is methyl, ethyl, n -propyl, isopropyl, n -butyl, isobutyl, sec -butyl, tert -butyl, 1,1-dimethoxyethyl, 1,1-diethoxyethyl, cyclobutyl, cyclopentyl or cyclohexyl
• R 10 is hydrogen, allyl, benzyl or trimethylsilyl.
• R 1 is methyl, ethyl, n -propyl, isopropyl, n -butyl, isobutyl, sec -butyl, tert -butyl, 1,1-dimethoxyethyl, 1,1-diethoxyethyl, cyclobutyl, cyclopentyl or cyclohexyl
• R 10 is hydrogen, allyl, benzyl or trimethylsilyl
• R 2 is hydrogen, methyl, ethyl, isopropyl, n -butyl, isobutyl, sec -butyl or tert -butyl
• R 3 is hydrogen.
• R 1 is ethyl or isopropyl
• R 10 is allyl, benzyl or trimethylsilyl
• R 2 is methyl, n -propyl or isopropyl
• R 3 is hydrogen
• R 1 is isopropyl
• R 10 is benzyl
• R 2 is methyl
• R 3 is hydrogen
• R 1 is isopropyl
• R 10 is allyl
• R 2 is methyl
• R 3 is hydrogen.
• R 1 is ethyl or isopropyl
• R 10 is allyl, benzyl or trimethylsilyl
• R 2 is methyl, n -propyl or isopropyl
• R 3 is hydrogen and X is chloro.
• R 1 is isopropyl
• R 10 is benzyl
• R 2 is methyl
• R 3 is hydrogen and X is chloro.
• R 1 is isopropyl
• R 10 is allyl
• R 2 is methyl
• R 3 is hydrogen and X is chloro.
• X is bromo or chloro. In another embodiment, X is chloro, bromo or iodo, R 10 is hydrogen, allyl, benzyl or trimethylsilyl, R 2 is hydrogen and R 3 is hydrogen. In still another embodiment, X is chloro, bromo or iodo, R 10 is hydrogen, allyl, benzyl or trimethylsilyl, R 2 is methyl and R 3 is hydrogen. In still another embodiment, X is chloro, bromo or iodo, R 10 is hydrogen, allyl, benzyl or trimethylsilyl, R 2 is ethyl and R 3 is hydrogen.
• X is chloro, bromo or iodo
• R 10 is hydrogen, allyl, benzyl or trimethylsilyl
• R 2 is propyl and R 3 is hydrogen.
• X is chloro, bromo or iodo
• R 10 is hydrogen, allyl, benzyl or trimethylsilyl
• R 2 is isopropyl and R 3 is hydrogen.
• X is chloro, bromo or iodo
• R 10 is hydrogen, allyl, benzyl or trimethylsilyl
• R 2 is butyl and R 3 is hydrogen.
• X is chloro, bromo or iodo
• R 10 is hydrogen, allyl, benzyl or trimethylsilyl
• R 2 is isobutyl and R 3 is hydrogen.
• X is chloro, bromo or iodo
• R 10 is hydrogen, allyl, benzyl or trimethylsilyl
• R 2 is sec -butyl and R 3 is hydrogen.
• X is chloro, bromo or iodo
• R 10 is hydrogen, allyl, benzyl or trimethylsilyl
• R 2 is tert -butyl and R 3 is hydrogen.
• X is chloro, bromo or iodo
• R 10 is hydrogen, allyl, benzyl or trimethylsilyl
• R 2 is cyclohexyl and R 3 is hydrogen.
• X is chloro, bromo or iodo
• R 10 is hydrogen, allyl, benzyl or trimethylsilyl
• R 2 is phenyl and R 3 is hydrogen.
• X is chloro, bromo or iodo
• R 10 is hydrogen, allyl, benzyl or trimethylsilyl
• R 2 is methyl and R 3 is methyl.
• X is chloro, bromo or iodo
• R 10 is hydrogen, allyl, benzyl or trimethylsilyl
• R 2 is methoxycarbonyl and R 3 is methyl
• X is chloro, bromo or iodo
• R 10 is hydrogen, allyl, benzyl or trimethylsilyl
• R 2 is ethoxycarbonyl and R 3 is methyl
• X is chloro, bromo or iodo
• R 10 is hydrogen, allyl, benzyl or trimethylsilyl
• R 2 is isopropoxycarbonyl and R 3 is methyl.
• X is chloro, bromo or iodo
• R 10 is hydrogen, allyl, benzyl or trimethylsilyl
• R 2 is cyclohexyloxycarbonyl and R 3 is methyl.
• X is chloro, bromo or iodo
• R 10 is hydrogen, allyl, benzyl or trimethylsilyl and R 2 and R 3 together with the atom to which they are attached form a cyclohexyl ring.
• X is chloro
• R 10 is hydrogen, allyl, benzyl or trimethylsilyl
• R 2 is hydrogen, methyl, ethyl, n -propyl, isopropyl, n -butyl, isobutyl, sec -butyl or tert -butyl and R 3 is hydrogen.
• X is chloro
• R 10 is hydrogen, allyl, benzyl or trimethylsilyl
• R 2 is methyl, n -propyl or isopropyl
• R 3 is hydrogen.
• X is chloro, R 10 is allyl, R 2 is methyl, and R 3 is hydrogen.
• X is chloro, R 10 is benzyl, R 2 is methyl, and R 3 is hydrogen.
• X is chloro, R 10 is trimethylsilyl, R 2 is methyl, and R 3 is hydrogen.
• the ratio of the compound of Formula (II) to the compound of Formula ( III ) is between about 1:1 and 1:20. In another embodiment, the ratio of the compound of Formula ( II ) to the compound of Formula ( III ) is between about 1:1 and 1:5. In still another embodiment, the ratio of the compound of Formula ( II ) to the compound of Formula ( III ) is about 1:1.
• the compounds of Formulae ( II ) and ( III ) and the metal salt are contacted with a solvent.
• the ratio of the compound of Formula ( II ) to the compound of Formula ( III ) is between about 1:1 and 1:20.
• the ratio of the compound of Formula ( II ) to the compound of Formula ( III ) is between about 1:1 and 1:5.
• the ratio of the compound of Formula ( II ) to the compound of Formula ( III ) is about 1:1.
• the solvent is dichloromethane, dichloroethane, chloroform, toluene, dimethylformamide, dimethylacetamide, N-methylpyrrolidinone, dimethyl sulfoxide, pyridine, ethyl acetate, acetonitrile, acetone, 2-butanone, methyl tert -butyl ether, methanol, ethanol, isopropanol, tert -butanol, water, hexamethylphosphoramide or combinations thereof.
• the metal is Ag, Hg, Na, K, Li, Cs, Ca, Mg or Zn.
• the compounds of Formulae ( II ) and ( III ) and the organic base are contacted with a solvent.
• the ratio of the compound of Formula ( II ) to the compound of Formula (III) is between about 1:1 and 1:20.
• the ratio of the compound of Formula ( II ) to the compound of Formula ( III ) is between about 1:15 and 1:20.
• the ratio of the compound of Formula ( II ) to the compound of Formula ( III ) is about 1:10.
• the ratio of the compound of Formula ( II ) to the compound of Formula ( III ) is between about 1:1 and 1:5.
• the ratio of the compound of Formula ( II ) to the compound of Formula ( III ) is about 1:1.
• the solvent is dichloromethane, dichloroethane, chloroform, toluene, dimethylformamide, dimethylacetamide, N-methylpyrrolidinone, dimethyl sulfoxide, pyridine, ethyl acetate, acetonitrile, acetone, 2-butanone, methyl tert -butyl ether, methanol, ethanol, isopropanol, tert -butanol, water, hexamethylphosphoramide or combinations thereof.
• the organic base is triethylamine, tributylamine, diisopropylethylamine, dimethylisopropylamine, N-methylmorpholine, N-methylpyrrolidine, N-methylpiperidine, pyridine, 2-methylpyridine, 2,6-dimethylpyridine, 4-dimethylaminopyridine, 1, 4-diazabicyclo[2.2.2]octane, 1, 8-diazabicyclo[5.4.0]undec-7-ene, 1, 5-diazabicyclo[4.3.0]undec-7-ene or combinations thereof.
• the compound of Formula ( III ) is a liquid under the conditions of said contacting, the compound of Formula ( III ) further serving as a solvent for the reaction with the compound of Formula ( II ).
• the compound of Formula ( III ) is acetic acid, methoxyacetic acid, ethoxyacetic acid, propionic acid, butyric acid, isobutyric acid, pivalic acid, valeric acid, isovaleric acid, 2-methylbutyric acid, cyclobutanecarboxylic acid, cyclopentanecarboxylic acid or cyclohexanecarboxylic acid.
• the compound of Formula ( III ) is isobutyric acid.
• the compound of Formula ( II ), the compound of Formula ( III ) and the metal salt are contacted at a temperature between about -25 °C and about 120 °C. In another embodiment, the temperature is between about 0 °C and about 25 °C.
• the compound of Formula ( II ), the compound of Formula ( III ) and the organic base are contacted at a temperature between about -25 °C and about 120 °C. In another embodiment, the temperature is between about 0 °C and about 25 °C.
• the compound of Formula ( II ), the compound of Formula ( III ) and the organic base are contacted with a catalytic amount of an iodide salt.
• the iodide salt is sodium iodide, potassium iodide, tetramethylammonium iodide, tetraethylammonium iodide or tetrabutylammonium iodide.
• R 2 and R 3 are independently hydrogen, alkyl, substituted alkyl, alkoxycarbonyl, substituted alkoxycarbonyl, aryl, substituted aryl, arylalkyl, substituted arylalkyl, carbamoyl, substituted carbamoyl, cycloalkyl, substituted cycloalkyl, heteroaryl or substituted heteroaryl.
• R 2 and R 3 are independently hydrogen, alkyl, alkoxycarbonyl, aryl, arylalkyl, carbamoyl, cycloalkyl or heteroaryl.
• R 2 and R 3 are independently hydrogen, alkanyl or substituted alkanyl. In still another embodiment, R 2 and R 3 are independently hydrogen or alkanyl. In still another embodiment, R 2 and R 3 together with the atom to which they are bonded form a cycloalkyl, substituted cycloalkyl, cycloheteroalkyl or substituted cycloheteroalkyl ring. In still another embodiment R 2 and R 3 together with the atom to which they are bonded form a cycloalkanyl ring.
• X is chloro, bromo or iodo. In another embodiment, X is chloro.
• X is chloro, bromo or iodo and R 2 and R 3 are independently hydrogen, alkyl, substituted alkyl, alkoxycarbonyl, substituted alkoxycarbonyl, aryl, substituted aryl, arylalkyl, substituted arylalkyl, carbamoyl, cycloalkyl, substituted cycloalkyl, heteroaryl, substituted heteroaryl, heteroarylalkyl or substituted heteroarylalkyl.
• X is chloro, bromo or iodo
• R 2 and R 3 are independently hydrogen, alkyl, substituted alkyl, alkoxycarbonyl, substituted alkoxycarbonyl, aryl, substituted aryl, arylalkyl, substituted arylalkyl, carbamoyl, cycloalkyl, substituted cycloalkyl, heteroaryl, substituted heteroaryl, heteroarylalkyl or substituted heteroarylalkyl.
• X is chloro and R 2 and R 3 are independently hydrogen, alkyl, substituted alkyl, alkoxycarbonyl, substituted alkoxycarbonyl, aryl, substituted aryl, arylalkyl, substituted arylalkyl, carbamoyl, cycloalkyl, substituted cycloalkyl, heteroaryl, substituted heteroaryl, heteroarylalkyl or substituted heteroarylalkyl.
• X is chloro, bromo or iodo
• R 2 and R 3 are independently hydrogen, alkyl, alkoxycarbonyl, aryl, arylalkyl, carbamoyl, cycloalkyl or heteroaryl.
• X is chloro, bromo or iodo
• R 2 and R 3 are independently hydrogen, alkanyl or substituted alkanyl.
• X is chloro, bromo or iodo, and R 2 and R 3 are independently alkanyl.
• X is chloro, bromo or iodo
• R 2 and R 3 together with the atom to which they are attached form a cycloalkyl, substituted cycloalkyl, cycloheteroalkyl or substituted cycloheteroalkyl ring.
• X is chloro, and R 2 and R 3 are independently hydrogen, alkyl, alkoxycarbonyl, aryl, arylalkyl, carbamoyl, cycloalkyl or heteroaryl. In still another embodiment, X is chloro, and R 2 and R 3 are independently hydrogen, alkanyl or substituted alkanyl. In still another embodiment, X is chloro, and R 2 and R 3 are independently alkanyl. In still another embodiment, X is chloro, and R 2 and R 3 together with the atom to which they are attached form a cycloalkanyl ring.
• R 2 and R 3 are independently hydrogen, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec -butyl, tert -butyl, cyclobutyl, cyclopentyl, cyclohexyl, methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, isopropoxycarbonyl, butoxycarbonyl, isobutoxycarbonyl, sec -butoxycarbonyl, tert -butoxycarbonyl, cyclohexyloxycarbonyl, phenyl, benzyl, phenethyl or 3-pyridyl.
• X is chloro, bromo or iodo
• R 2 and R 3 are independently hydrogen, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec -butyl, tert -butyl, cyclobutyl, cyclopentyl, cyclohexyl, methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, isopropoxycarbonyl, butoxycarbonyl, isobutoxycarbonyl, sec -butoxycarbonyl, tert -butoxycarbonyl, cyclohexyloxycarbonyl, phenyl, benzyl, phenethyl or 3-pyridyl.
• X is chloro, bromo or iodo
• R 2 and R 3 together with the atom to which they are attached form a cyclobutyl, cyclopentyl or cyclohexyl ring.
• R 2 is methyl, ethyl, n -propyl, isopropyl, n -butyl, isobutyl, sec -butyl, tert -butyl, cyclohexyl or phenyl and R 3 is hydrogen.
• R 2 is methyl, methoxycarbonyl, ethoxycarbonyl, isopropoxycarbonyl or cyclohexyloxycarbonyl and R 3 is methyl.
• X is chloro, bromo or iodo
• R 2 is methyl, ethyl, n -propyl, isopropyl, n -butyl, isobutyl, sec -butyl, tert -butyl, cyclohexyl or phenyl and R 3 is hydrogen.
• R 10 is hydrogen, alkyl, substituted alkyl, aryl, substituted aryl, arylalkyl, substituted arylalkyl, aryldialkylsilyl, cycloalkyl, substituted cycloalkyl, cycloheteroalkyl, substituted cycloheteroalkyl, heteroalkyl, substituted heteroalkyl, heteroaryl, substituted heteroaryl, heteroarylalkyl, substituted heteroarylalkyl or trialkylsilyl.
• R 10 is hydrogen.
• R 10 is alkanyl, substituted alkanyl, alkenyl, substituted alkenyl, aryl, substituted aryl, arylalkyl, substituted arylalkyl, aryldialkylsilyl or trialkylsilyl.
• R 10 is allyl.
• R 10 is benzyl.
• R 10 is trimethylsilyl.
• n is 0. In another embodiment, n is 1.
• R 4 is hydrogen.
• R 5 is selected from the group consisting of hydrogen, alkanyl, substituted alkanyl, aryl, substituted aryl, arylalkanyl, substituted arylalkanyl, cycloalkanyl, heteroarylalkyl and substituted heteroarylalkanyl.
• R 5 is selected from the group consisting of hydrogen, alkanyl and cycloalkanyl.
• R 5 is selected from the group consisting of hydrogen, methyl, isopropyl, isobutyl, sec -butyl, tert -butyl, cyclopentyl and cyclohexyl.
• R 5 is selected from the group consisting of substituted alkanyl.
• R 5 is selected from the group consisting of -CH 2 OH, -CH(OH)CH 3 , -CH 2 CO 2 H, -CH 2 CH 2 CO 2 H, -CH 2 CONH 2 , -CH 2 CH 2 CONH 2 , - CH 2 CH 2 SCH 3 , CH 2 SH, -CH 2 (CH 2 ) 3 NH 2 and -CH 2 CH 2 CH 2 NHC(NH)NH 2 .
• R 5 is selected from the group consisting of aryl, arylalkanyl, substituted arylalkanyl and heteroarylalkanyl.
• R 5 is selected from the group consisting of phenyl, benzyl, 4-hydroxybenzyl, 4-bromobenzyl, 4-imidazolylmethyl and 3-indolylmethyl.
• R 4 and R 5 together with the atoms to which they are attached form a cycloheteroalkyl or substituted cycloheteroalkyl ring. In still another embodiment, R 4 and R 5 together with the atoms to which they are attached form an azetidine, pyrrolidine or piperidine ring.
• R 6 and R 9 are independently selected from the group consisting of hydrogen, alkyl, substituted alkyl, aryl, substituted aryl, cycloalkyl and substituted cycloalkyl. In another embodiment, R 6 and R 9 are independently selected from the group consisting of hydrogen and alkanyl. In still another embodiment, R 6 and R 9 are both hydrogen.
• R 7 and R 8 are independently selected from the group consisting of hydrogen, alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl, cycloheteroalkyl and substituted cycloheteroalkyl. In another embodiment, R 7 and R 8 are independently selected from the group consisting of hydrogen, alkanyl and substituted alkanyl. In still another embodiment, R 7 is hydrogen and R 8 is selected from the group consisting of C 1-6 alkanyl.
• R 7 and R 8 together with the carbon atom to which they are attached are cycloalkanyl or substituted cycloalkanyl.
• R 7 and R 8 together with the carbon atom to which they are attached are selected from the group consisting of cyclobutyl, substituted cyclobutyl, cyclopentyl, substituted cyclopentyl, cyclohexyl and substituted cyclohexyl.
• R 7 and R 8 together with the carbon atom to which they are attached are cycloheteroalkyl or substituted cycloheteroalkyl.
• R 7 and R 8 together with the carbon atom to which they are attached are bridged cycloalkyl.
• a compound of Formula ( II ) is derived from a GABA analog of Formula ( IV ): wherein the GABA analog of Formula ( IV ) is selected from the group consisting of
• the compound of Formula ( II ) is a compound of Formulae ( VII ) or ( VIII ):
• n is 0. In another embodiment, n is 1.
• R 4 is hydrogen.
• R 5 is selected from the group consisting of hydrogen, alkanyl, substituted alkanyl, aryl, substituted aryl, arylalkanyl, substituted arylalkanyl, cycloalkanyl, heteroarylalkyl and substituted heteroarylalkanyl.
• R 5 is selected from the group consisting of hydrogen, methyl, isopropyl, isobutyl, sec -butyl, tert -butyl, cyclopentyl, cyclohexyl, -CH 2 OH, -CH(OH)CH 3 , -CH 2 CO 2 H, -CH 2 CH 2 CO 2 H, -CH 2 CONH 2 , -CH 2 CH 2 CONH 2 , - CH 2 CH 2 SCH 3 , CH 2 SH, -CH 2 (CH 2 ) 3 NH 2 and -CH 2 CH 2 CH 2 NHC(NH)NH 2 , phenyl, benzyl, 4-hydroxybenzyl, 4-bromobenzyl, 4-imidazolylmethyl and 3-indolylmethyl.
• R 4 and R 5 together with the atoms to which they are attached form a cycloheteroalkyl or substituted cycloheteroalkyl ring. In still another embodiment, R 4 and R 5 together with the atoms to which they are attached form an azetidine, pyrrolidine or piperidine ring.
• X is chloro, bromo or iodo
• R 10 is hydrogen, allyl, benzyl or trimethylsilyl
• R 2 is hydrogen and R 3 is hydrogen
• X is chloro, bromo or iodo
• R 10 is hydrogen, allyl, benzyl or trimethylsilyl
• R 2 is methyl and R 3 is hydrogen
• X is chloro, bromo or iodo
• R 10 is hydrogen, allyl, benzyl or trimethylsilyl
• R 2 is ethyl and R 3 is hydrogen.
• X is chloro, bromo or iodo
• R 10 is hydrogen, allyl, benzyl or trimethylsilyl
• R 2 is propyl and R 3 is hydrogen.
• X is chloro, bromo or iodo
• R 10 is hydrogen, allyl, benzyl or trimethylsilyl
• R 2 is isopropyl and R 3 is hydrogen.
• X is chloro, bromo or iodo
• R 10 is hydrogen, allyl, benzyl or trimethylsilyl
• R 2 is butyl and R 3 is hydrogen.
• X is chloro, bromo or iodo
• R 10 is hydrogen, allyl, benzyl or trimethylsilyl
• R 2 is isobutyl and R 3 is hydrogen.
• X is chloro, bromo or iodo
• R 10 is hydrogen, allyl, benzyl or trimethylsilyl
• R 2 is sec -butyl and R 3 is hydrogen.
• X is chloro, bromo or iodo
• R 10 is hydrogen, allyl, benzyl or trimethylsilyl
• R 2 is tert -butyl and R 3 is hydrogen.
• X is chloro, bromo or iodo
• R 10 is hydrogen, allyl, benzyl or trimethylsilyl
• R 2 is cyclohexyl and R 3 is hydrogen.
• X is chloro, bromo or iodo
• R 10 is hydrogen, allyl, benzyl or trimethylsilyl
• R 2 is phenyl and R 3 is hydrogen.
• X is chloro, bromo or iodo
• R 10 is hydrogen, allyl, benzyl or trimethylsilyl
• R 2 is methyl and R 3 is methyl.
• X is chloro, bromo or iodo
• R 10 is hydrogen, allyl, benzyl or trimethylsilyl
• R 2 is methoxycarbonyl and R 3 is methyl
• X is chloro, bromo or iodo
• R 10 is hydrogen, allyl, benzyl or trimethylsilyl
• R 2 is ethoxycarbonyl and R 3 is methyl
• X is chloro, bromo or iodo
• R 10 is hydrogen, allyl, benzyl or trimethylsilyl
• R 2 is isopropoxycarbonyl and R 3 is methyl.
• X is chloro, bromo or iodo
• R 10 is hydrogen, allyl, benzyl or trimethylsilyl
• R 2 is cyclohexyloxycarbonyl
• R 3 is methyl
• X is chloro, bromo or iodo
• R 10 is hydrogen, allyl, benzyl or trimethylsilyl
• R 2 and R 3 together with the atom to which they are attached form a cyclohexyl ring.
• X is chloro
• R 10 is hydrogen, allyl, benzyl or trimethylsilyl
• R 2 is hydrogen, methyl, ethyl, n -propyl, isopropyl, n -butyl, isobutyl, sec -butyl or tert -butyl and R 3 is hydrogen.
• X is chloro
• R 10 is hydrogen, allyl, benzyl or trimethylsilyl
• R 2 is methyl, n -propyl or isopropyl
• R 3 is hydrogen.
• X is chloro, R 10 is allyl, R 2 is methyl, and R 3 is hydrogen.
• X is chloro, R 10 is benzyl, R 2 is methyl, and R 3 is hydrogen.
• X is chloro, R 10 is trimethylsilyl, R 2 is methyl, and R 3 is hydrogen.
• starting materials useful for preparing compounds and intermediates thereof, and/or practicing methods of the invention are commercially available or can be prepared by well-known synthetic methods.
• Other methods for synthesis of the prodrugs described herein are either described in the art or will be readily apparent to the skilled artisan in view of the references provided above and may be used to synthesize the compounds of the invention. Accordingly, the methods presented in the Schemes herein are illustrative rather than comprehensive.
• the carboxylic acid moiety in ( 2 ) is esterified to yield compound ( 3 ), either (i) via alkylation with R 10 -Y, where Y is halide, O 3 SR' (R' is alkyl, substituted alkyl, aryl or substituted aryl), or other suitable leaving group), or (ii) via condensation with alcohol R 10 -OH under standard acylation conditions (e.g ., in the presence of a coupling agent such as a carbodiimide, via an acyl halide, acid anhydride or other activated ester intermediate).
• a coupling agent such as a carbodiimide
• compound ( 4 ) Removal of the protecting group from ( 3 ) under standard deprotection conditions affords compound ( 4 ).
• the protecting group Pg is removable under acidic conditions and compound ( 4 ) is isolated as a salt, which is stabilized towards lactam formation relative to the corresponding free base form.
• tert -Butoxycarbonyl i.e ., Boc
• Boc is one preferred protecting group, and may be removed with HCl to afford ( 4 ) as a hydrochloride salt.
• the hydrochloride salt of ( 4 ) is prepared directly from (1) by treatment with an excess of thionyl chloride or hydrogen chloride gas and alcohol R 10 -OH (Scheme 2).
• Typical ratios of ( 1 ) to thionyl chloride from between 1:1 and 1:20, and ratios of ( 1 ) to alcohol from between 1:1 and 1:20 may be used.
• the reaction may be performed at temperatures between -20 °C and 25°C. Under conditions where the alcohol R 10 -OH is a liquid, the alcohol may be used as a solvent for the reaction.
• reaction may be performed in the presence of a suitable solvent, such as, for example, dichloromethane, dichloroethane, chloroform, toluene, dimethylformamide, dimethylacetamide, N-methylpyrrolidinone, or pyridine.
• a suitable solvent such as, for example, dichloromethane, dichloroethane, chloroform, toluene, dimethylformamide, dimethylacetamide, N-methylpyrrolidinone, or pyridine.
• Preferred alcohols R 10 -OH for this reaction are arylalkyl, substituted arylalkyl and allylic alcohols. Allyl alcohol and benzyl alcohol are particularly preferred.
• a compound of formula ( II ) is prepared by acylation of ( 4 ) with compound ( 5 ) (see Scheme 3), where X is halide and Z is a leaving group ( e.g ., halide, p -nitrophenolate, imidazolyl, etc .).
• X is Cl or Br and Z is Cl. More preferably, X and Z are both Cl.
• the acylation reaction may be performed in the presence of a base, including inorganic and organic bases (e.g ., tertiary amine bases, such as triethylamine, tributylamine, diisopropylethylamine, dimethylisopropylamine, N-methylmorpholine, N-methylpyrrolidine, N-methylpiperidine, pyridine, 2-methylpyridine, 2,6-dimethylpyridine, 4-dimethylaminopyridine, 1, 4-diazabicyclo[2.2.2]octane, 1, 8-diazabicyclo[5.4.0]undec-7-ene, 1, 5-diazabicyclo[4.3.0]undec-7-ene, etc.).
• bases including inorganic and organic bases (e.g ., tertiary amine bases, such as triethylamine, tributylamine, diisopropylethylamine, dimethylisopropylamine, N-methylmorpho
• Suitable solvents for this acylation include, but are not limited to, dichloromethane, dichloroethane, chloroform, toluene, dimethylformamide, dimethylacetamide, N-methylpyrrolidinone, dimethyl sulfoxide, pyridine, ethyl acetate, isopropyl acetate, acetonitrile, acetone, 2-butanone, methyl tert -butyl ether, or combinations thereof.
• biphasic solvent mixtures comprising water and one or more of dichloromethane, dichloroethane, chloroform, toluene, ethyl acetate, isopropyl acetate or methyl tert -butyl ether, may be utilized.
• Typical temperatures for performing this reaction are between -20 °C and 50°C, more preferably, between -20 °C and 25°C.
• a compound of formula ( II ), where R 10 is trialkylsilyl or aryldialkylsilyl may be prepared directly from compound ( 1 ) by silylation (e.g ., using a silyl halide or silylamide reagent) and then acylation of the resulting intermediate with compound ( 5 ) (see Scheme 4).
• Suitable solvents for performing this reaction include, but are not limited to, dichloromethane, dichloroethane, chloroform, toluene, pyridine, and acetonitrile.
• Suitable bases for performing this reaction include, but are not limited to, triethylamine, tributylamine, diisopropylethylamine, dimethylisopropylamine, N-methylmorpholine, N-methylpyrrolidine, N-methylpiperidine, pyridine, 2-methylpyridine, 2,6-dimethylpyridine, 4-dimethylaminopyridine, 1, 4-diazabicyclo[2.2.2]octane, 1, 8-diazabicyclo[5.4.0]undec-7-ene or 1, 5-diazabicyclo[4.3.0]undec-7-ene.
• Typical temperatures for performing this reaction are between -78 °C and 50°C, more preferably, between -20 °C and 25°C.
• R 10 is a carboxylic acid protecting group that can be removed under mild conditions to provide a compound of formula ( I ) where R 10 is hydrogen.
• Carboxylic acid protecting groups removable via mild acidic hydrolysis, fluoride ion-promoted hydrolysis, catalytic hydrogenolysis, transfer hydrogenolysis, or other transition metal-mediated deprotection reactions are preferred.
• R 10 is trimethylsilyl, allyl or benzyl.
• the invention is further defined by reference to the following examples, which describe in detail the preparation of 1-haloalkyl carbamates of GABA analogs and illustrate methods of synthesizing 1-(acyloxy)-alkyl carbamates of GABA analogues from 1-haloalkyl carbamates of GABA analogs. It will be apparent to those skilled in the art that many modifications, both to materials and methods, may be practiced without departing from the scope of the invention.
• a dry 500 mL, three-necked, round-bottomed flask was fitted with a magnetic stirring bar and a 60 mL pressure-equalizing addition funnel and flushed with nitrogen gas.
• the flask was charged with gabapentin (17.1 g, 0.1 mol) and benzyl alcohol (128 mL, 1.18 mol) and the mixture was cooled to 0°C with an ice-water bath.
• Thionyl chloride (51.8 mL, 77.25 g, 0.65 mol) was added dropwise to the stirred solution over a period of 1 h.
• the reaction was monitored by LC/MS, with product and unreacted gabapentin hydrochloride being observed.
• the reaction mixture contained residual gabapentin hydrochloride (by LC/MS). Additional thionyl chloride (20 mL, 30 g, 0.25 mol) was added at 0°C, and the reaction mixture allowed to stir at room temperature for another 12 h (LC/MS shows traces of residual gabapentin hydrochloride). A final portion of thionyl chloride (10 mL, 15 g, 0.12 mol) was added at 0°C and the reaction mixture allowed to stir at room temperature for 4 h (LC/MS showed no remaining gabapentin hydrochloride). The reaction mixture was then diluted with ethyl ether (200 mL) and cooled to 0° C while stirring.
• Gabapentin (700 g , 4.09 mol) was slurried in water (2.7 L) with potassium carbonate (1.2 kg, 8.58 mol) and mechanically stirred under a nitrogen atmosphere.
• Di- tert -butyl dicarbonate (875 g, 4.00 mol) was dissolved in dioxane (4 L) and was added in large aliquots while maintaining the pH at 8 - 10, and if needed, adjusting the pH using additional potassium carbonate. The reaction was monitored by 1 H-NMR, noting the disappearance of the singlet resonance at 1.22 ppm for di- tert -butyl dicarbonate.
• the crude reaction mixture was split in two equal batches, each of which was diluted with diethyl ether (6 L), washed with water (6 x 2L) in a centrifugal extractor to remove excess isobutyric acid, followed by washing with 10% potassium bicarbonate (4 x 2 L) and brine (2 x 2 L) before drying over anhydrous sodium sulfate.
• the combined organic extracts were concentrated to provide a dark orange oil (916 g).
• the crude oil (400 g) was loaded onto an 800 g Biotage TM silica gel chromatography column and eluted with 5% ethyl acetate in hexane (6 L), then with 7% ethyl acetate in hexane (12 L).
• the resulting sodium salt ( 12 ) was scraped from the flasks as a hygroscopic solid and transferred quickly into bottles, which were immediately capped and transferred into a drying chamber at 14% relative humidity (RH).
• RH relative humidity
• the remaining oily product in the flasks was dissolved in diethyl ether and concentrated in vacuo at 25 °C, then dried under high vacuum until a dry foam was produced.
• a dry 500 mL, three-neck, round-bottomed flask was fitted with a magnetic stirring bar and a 100 mL pressure-equalizing addition funnel and flushed with nitrogen gas.
• the flask was charged with gabapentin (17.1 g, 0.1 mol) and allyl alcohol (100 mL, 1.46 mol) and the entire mixture was cooled to 0°C in an ice-water bath.
• Thionyl chloride (22.5 mL, 36 g, 0.3 mol) was added drop-wise over a period of 30 min to the stirred solution, and the reaction mixture allowed to stir for 16 h at room temperature.
• the mixture was then diluted with diethyl ether (200 mL) and cooled to 0°C while stirring.
• the product was recrystallized using 1:10 ethyl acetate: heptane (100 mL) to give the product ( 11 ) as a white, crystalline solid (7.9 g, 88%), m.p 63-64°C.
• Method B To a stirred solution of compound ( 15 ) (1 g, 2.7 mmol) in acetonitrile (10 mL) under nitrogen was added (10 mg, 0.008 mmol) of tetrakis(triphenylphosphine) palladium (0) followed by morpholine (0.28 mL, 0.28 g, 3.2 mmol). After one hour, the solvent was removed in vacuo. The resulting oil was dissolved in diethyl ether (50 mL) and the organic phase was washed with 2N HCl (20 mL), water (20 mL) and brine (20 mL).
• the crude compound was purified by column chromatography on silica gel, eluting with 30% ethyl acetate : hexane to give the desired product ( 11 ) as a colorless oil, which solidified on further standing at room temperature for 12 h (0.70 g, 78% yield), m.p. 62-64°C.
• the resulting silyl ester ( 19 ) was converted via acidic work-up to the corresponding acid ( 18 ) by washing the reaction mixture with water (2 x 1 L), followed by 1N HCl (2 x 1 L) then brine (2 x 500 mL). After drying over anhydrous sodium sulfate and removal of the solvent in vacuo, the crude product (116 g, 60% yield) was obtained as an off-white solid and used in Example 16 without further purification.
• Example 17 1- ⁇ [( ⁇ -Chloroisobutoxy)carbonyl]aminomethyl ⁇ -1-Cyclohexane Acetic Acid (21) via Trimethylsilyl 1- ⁇ [(1( ⁇ -Chloroisobutoxy)-carbonyl]aminomethyl ⁇ -1-Cyclohexane Acetate (22)
• the resulting silyl ester ( 22 ) was converted via acidic work-up to the corresponding acid ( 21 ) by washing the reaction mixture with 10% citric acid (30 mL) and the organic layer separated. The aqueous layer was further extracted with ether (3 x 20 mL) and the combined organic phases were dried over MgSO 4 and then concentrated in vacuo. Chromatography of the residue on silica gel, eluting with hexane: ethyl acetate (1:4) gave the title compound ( 21 ) (2.37g, 77%).
• the resulting silyl ester ( 32 ) was converted via acidic work-up to the corresponding acid ( 31 ) by quenching the reaction mixture with citric acid, diluting with dichloromethane, washing with water and brine; then drying over anhydrous Na 2 SO 4 . Filtration and evaporation afforded the title compound ( 31 ) (300 mg), which was used in the following example without further purification.
• Example 28 3- ⁇ [( ⁇ -Chloroisobutoxy)carbonyl]aminomethyl ⁇ -5-Methyl-Hexanoic Acid (34) via Trimethylsilyl 3- ⁇ [( ⁇ -Chloroisobutoxy)carbonyl]-aminomethyl ⁇ -5-Methyl-Hexanoate (35)
• the resulting silyl ester ( 35 ) was converted via acidic work-up to the corresponding acid ( 34 ) by quenching the reaction mixture with citric acid, diluting with dichloromethane, washing with water and brine, then drying over anhydrous Na 2 SO 4 . Filtration and evaporation afforded the title compound ( 34 ) (300 mg), which was used in the following example without further purification.

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